Method and device for autonomous braking of a vehicle following collision

ABSTRACT

A method of controlling a vehicle includes providing a vehicle having a brake system configured to operate according to a nominal mode in which applied braking pressure is based on a driver braking request, a first active braking mode in which applied braking pressure is based on maximum ABS braking pressure and decreased in response to a driver brake pedal release, and a second active braking mode in which applied braking pressure is based on maximum braking pressure. In response to a detected collision, the system is controlled according to the first active braking mode. In response to the first active braking mode being active and no driver braking request being anticipated, the system is controlled according to the second active braking mode. In response to the first or second active braking modes being active and a termination criterion being satisfied, the system is controlled according to the nominal mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/489,787 filed Sep. 18, 2014, which is a continuation of co-pendingU.S. patent application Ser. No. 13/791,526 filed Mar. 8, 2013, whichclaims priority to German Patent Application No. DE 102012203733.0titled “Method and Device for Autonomous Braking of a Vehicle Followinga First Collision” filed Mar. 9, 2012, which are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

The present invention relates to vehicle braking controls and collisionmitigation control algorithms and devices.

BACKGROUND

During a collision, a vehicle can generate or exhibit predeterminedmovements indicative of a probability of collision. Modern vehicles canincorporate collision mitigation systems (CMS) or collision avoidancefor driver assistance systems (CADS). Still, there exists a desire foradditional post-collision mitigation systems.

SUMMARY

The present disclosure addresses one or more of the above-mentionedissues. Other features and/or advantages will become apparent from thedescription which follows.

One advantage of the present disclosure is that it provides analternative post-collision mitigation system to existing collisionmitigation systems.

One exemplary embodiment relates to a method for autonomous braking of amotor vehicle during a collision, the method including: (i) detecting acollision; (ii) detecting a predetermined movement by the motor vehiclefollowing the collision; and (iii) initiating an autonomous brakingprocess if a driver has not initiated the braking process.

One exemplary embodiment relates to a device for autonomously braking amotor vehicle following a collision, including: a controller having: (i)a braking algorithm; and (ii) a detection unit configured to detect apredetermined movement of the motor vehicle and detect the collision.The braking algorithm is configured to output a signal for initiatingthe braking process according to detection of the predetermined movementand a collision.

Another exemplary embodiment relates to a method controlling a vehiclebraking system, the method including: (i) detecting whether a collisionhas occurred; (ii) detecting whether a predetermined condition followsthe collision; (iii) determining whether a driver has applied thebrakes; and (iv) wherein when a driver has not applied the brakes,autonomously initiating braking.

The invention will be explained in greater detail below by way ofexample with reference to the figures, in which the same referencenumbers are used in the figures for identical or essentially identicalelements. The above features and advantages and other features andadvantages of the present teachings are readily apparent from thefollowing detailed description for carrying out the invention when takenin connection with the accompanying drawings. In the figures:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic depiction of an autonomous braking system for amotor vehicle.

FIG. 2 is a schematic depiction of collision detection logic for thesystem of FIG. 1.

FIG. 3 is a plot of a brake pressure profile against time for a brakingsystem.

FIG. 4 is a sensitivity rating chart for collision detection systems.

FIG. 5 illustrates a chronology profile for collision detectionaccording to the system of FIG. 1.

FIG. 6 is a flow diagram of a method for autonomous braking of a motorvehicle according to an exemplary embodiment of the present disclosure.

FIG. 7 is a diagram for an exemplary triggering of interruption of afuel supply.

FIG. 8 illustrates a chronology profile for braking control.

The drawings are only used to explain the invention and do not restrictit. The drawings and the individual parts are not necessarily to scale.The same reference numbers denote the same or similar parts.

DETAILED DESCRIPTION

Turning now to the figures, there is shown a method for controlling avehicle braking system independent of driver input. A system foreffectuating the same is also illustrated.

According to a first aspect of the invention, a method for autonomousbraking of a motor vehicle includes the following steps: (1) detecting afirst collision; (2) detecting a predetermined (and in some instances anundesirable) movement of the motor vehicle following the collision; (3)initiation of an autonomous braking process after detecting thecollision and predetermined movement, if a driver has not initiated abraking process.

The autonomous braking strategy seeks to reduce kinetic energy of themotor vehicle during a collision event. The autonomous braking process,i.e. a braking process initiated and carried out by the brake system orcontrol system, can be initiated independent of the driver. Thus, forexample, in the event of a driver initiated braking process, anautonomous braking process can be initiated which then overrides thedriver braking process. In one embodiment, an autonomous braking processis initiated if an undesirable movement is detected following a driveraborted braking process. Thus, the consequences of human error or animpairment of the driver as a result of the collision can be mitigated.

Following detection of the collision, the brake system can be preloaded,for example by requesting a small amount of braking force and/or byreducing the trigger threshold of the brake system, thus enabling afaster response. With the request for a small amount of braking forcethe brake calipers are moved closer to the brake disk in order to allowfaster response.

The movement of the motor vehicle can be monitored in response to thebraking process—that of the driver and/or the autonomous one. Thereaction of the driver can be monitored in response to the brakingprocess. This can support the decision as to whether and in what form anautonomous braking process is initiated, maintained and/or ended or inwhat form the driver or the vehicle is assisted.

In one embodiment, the collision is detected from activation of anairbag, from the fuel supply being cut off and/or from measured valuesof at least one motion sensor. Using the measurement values and/orcalculations for speed changes, the severity (or a severity rating) ofthe accident can be computed. Thus, for example, multiple values can becompared with predefined threshold. The intensity of the accident or theaccident severity can be computed or estimated therefrom. Thisinformation can be used for the autonomous brake system and/or othersystems for adequate countermeasures.

The support for the brake system can be terminated following thefulfillment of a termination criterion. It can be provided to activatethe support of the brake system for only a specific emergency situationtime interval and thereafter to return to normal operation or adifferent state. The termination criterion can, for example, bestabilization of the motor vehicle, whereby the normal safety systemsare again functional for a specific time period, e.g. 2.5 seconds, orthe motor vehicle is stationary.

According to a further aspect of the invention, a device for autonomousbraking in a motor vehicle following a collision comprises a controllerwith a braking algorithm; whereby the controller comprises a detectionunit for a collision, a detection unit for an undesirable movement ofthe motor vehicle and a signal output for a brake control signal forinitiating the braking process according to the braking algorithm basedon the detection of the collision and the undesirable movement. Thisdevice can carry out the method described above efficiently and safely.The same advantages and modifications apply.

The device for braking support in one arrangement includes a sensingmeans for detecting the collision, whereby the sensing means producesthe collision signal. If the sensing means is part of the device forbraking support, this can have the advantage of a clearly defined andcomplete system, which, for example, comes into effect in the productionand maintenance of software or for any upgrades. The sensing meansincludes a speed, yaw rate, acceleration, air pressure, image processingand/or sound sensor.

Referring now the figures, FIG. 1 shows a schematic depiction of acircuit diagram for a device for autonomous braking. A braking device 1for a motor vehicle assists a driver of the motor vehicle during abraking process, in particular following a collision. The braking deviceor system 1 includes a controller 2, in which a braking algorithm 3 isdeposited, for example in a non-volatile memory.

The controller 2 is connected to a brake pedal encoder 4 and a gas pedalencoder 5, which, for example, is configured to measure a force or speedof a pedal movement by the driver and output a corresponding measurementvalue to the controller 2. An actuator 6 of the brake system, such asfor example a hydraulic pump or an active brake booster is controlledaccordingly by the controller 2 in order to prepare or initiate abraking process.

Furthermore, the controller 2 is connected to a sensing means 7 forcollision detection. The sensing means 7 here comprises accelerationsensors 8 for recording longitudinal and lateral accelerations, motionsensors 9 for recording yaw and roll rates and speed sensors 10 forrecording wheel speeds. These sensors provide signals to the controller2, which detects a collision using the signals via collision detectionlogic or a detection unit 11. Other inputs for detecting a collision canbe, for example, various flags, such as triggering of an airbag or aninterruption of fuel supply. Controller 2 can also be connected to otherdriver assistance systems.

Furthermore, controller 2 contains a detection unit 12, as shown in FIG.1, for detecting a predetermined movement of the motor vehicle.Detection unit 12 detects an undesirable movement on the basis of thesignals, e.g., of wheel speed, acceleration or motion sensors. Anundesirable movement can, for example, be detected from an abrupt changeof the speed or distance.

FIG. 2 shows a detailed illustration of the detection unit for acollision 11. The sensing means 7 includes, for example, satelliteaccelerometers, which are arranged on a front and the sides of the motorvehicle. These sensors typically have ranges of about −250 g through+250 g. Furthermore, the longitudinal and lateral acceleration valuesfrom a restraint system, such as a Restraint Control Module (or RCM) canbe used as inputs. These sensors typically have ranges of about −50 gthrough +50 g.

The speed of the motor vehicle and signals from motion sensors areprovided as other inputs. In some cases, wheel speeds or vehicle speedsbased on the gearbox or the force transfer are good indicators of thespeed of the vehicle. Thus, it can be advisable to determine a referencespeed of the vehicle that is based on various speed estimates during theperiod of PIB activation. Information from motion sensors, such as a yawrate and a roll rate, which are used, for example, in brake controlmodules (BCMs), can also be used.

In some embodiments, a driver intention is detected from gas pedalposition, the brake pedal position and the steering angle.

These inputs are connected to logic 13 for detection of an impact or acollision. The purpose of this logic 13 is to detect a collision thateither produces an instability of the vehicle or a significant change ofthe initial kinetic energy of the vehicle, as soon as possible. Thecollision can either impart rotational energy or translational energy tothe vehicle.

The logic 13 for detection of a collision carries out variouscomputations 14 such as a change of speed, energy and vehicledisplacement. These computations are filtered, for example with a lowpass filter 15. The result is the detection 16 of a collision. Thisresult is assured with confirmation functions 17 and protectivefunctions 18.

The algorithm for the detection of a collision is used to activatecountermeasures that have been specified by the brake system 1, of FIG.1, and/or other controllers. The algorithm or the calculation detectsall types of collisions that lead to an increase in the speed of thevehicle, produce a rotation of the vehicle or produce a loss of controlover the vehicle. A result of the algorithm does not just have to belimited for triggering an airbag. A sensitivity of the logic 13 or ofthe algorithm should be higher, in particular significantly higher, thanthat of the restraining modules or controllers.

FIG. 3 shows an illustration of a braking pressure against time. Line,L, shows a braking pressure profile produced or requested by the driver.Line, A, shows a braking pressure of the brake assistance system. Thebrake assistance system regulates the braking pressure to a full ABSbraking pressure and slowly takes the pressure off when a driverreleases the brake pedal. If the driver, upon detection of a collisionand an undesirable movement following collision, does not initiate abraking process, an autonomous braking process is initiated that sendsan active request for a braking pressure that can be limited by the ABS.

If the driver releases the brake pedal during braking and the vehicle isstill showing undesirable movements, an autonomous braking process isinitiated. The response of the motor vehicle to the braking processesfollowing the collision can be monitored. Thus decisions can besupported, as to how the current brake operations can be adapted orwhether the brake operations can be aborted.

The reaction of the driver to the braking processes can be monitored, inorder to support the decision between the braking modes, for example,the change from autonomous braking (AB) to braking assistance, or inorder to terminate an active braking operation, if there is a clearindication that the driver can control the movement of the vehicle.

The autonomous braking process can be terminated if the vehicle isstabilized in a region that can be managed by ESC or normal CMSfunctions, or if the time period since the collision is long enough, forexample 2.5 seconds, or if the vehicle has stopped or if there is adriver override, for example if the driver has activated the gas pedalfor the first time.

There can be a conflict resolution between received data. It can thus beexcluded that part or all of the brake assistance system is shut downbecause of a sensor fault, possibly caused by the collision.Furthermore, safety systems can be provided with a priority, for examplean impact-based brake assistance system can be allocated a higherpriority or credibility than a brake assistance system that is based onan image processing sensor. Thus different safety systems or controlsystems, which could request braking processes via the same interfaces,can be compared or coordinated.

FIG. 4 shows the difference between the intensities of a collisiondetected by the algorithm for the detection of a collision and thetriggering of an airbag. The intensity or the degree of intensity of thecollision is measured on the basis of a measured change in speed(Delta-V) or calculated speed changes. The sensitivity of the algorithmis approximately twice as great as for an airbag system, i.e., thetriggering threshold is about half the magnitude. An accident severityof the collision is computed in a computational unit 19, as shown inFIG. 2, using the calculations and/or the reference values. Thedetection unit for a collision 11 (of FIG. 2) then outputs a signal thatindicates a collision with a degree of intensity of the collision. Thetwo components of the signal, i.e. confirmation of the collision and thedegree of intensity of the collision, can be output together or with atime offset.

In addition to the function of preparation of the required informationfor initiating countermeasures following a collision, the results of thedetection unit for a collision 11 are also used for a vehicle statecalculation 20, for example, to update longitudinal and lateral speedsfollowing a collision.

FIG. 5 shows the chronology and interactions of an algorithm for thedetection of a collision with other systems following a collision 21.Following a collision event 21, the detection unit 11 confirms whethercollision has occurred or not. As soon as the collision has beenconfirmed by the detection unit 11, the relevant information is passedto a state calculation 20 and to one or more controllers 22.

The algorithms for a frontal impact, a side impact and an interruptionof the fuel supply can also trigger autonomous braking following acollision. In the frontal and lateral impact algorithms, additionalcalculations are carried out in order to activate restrainingmechanisms, such as an airbag and a tensioner. Likewise, the lateralimpact algorithm can use additional satellite pressure sensors in itscalculation and the frontal impact algorithm can use the yaw rate sensorin its calculation.

The function for the detection of a collision can be extended by the useof data of ambient sensors or ambient motion sensors prior to thecollision, in order to determine the exact position and the surroundingsof the vehicle prior to and during the collision. These items ofinformation can help to predict the degree of severity of the collisionand/or to adapt reference thresholds or values, in order, for example,to set a fast or slow response. The following types of information canbe used as a motion sensor; the vehicle's speed during the collision,the position of the vehicle during the collision, such as for example,being positioned on an expressway, in rural or urban area, and in thepresence of other objects at the front, the sides and the rear of thevehicle.

The position of the vehicle can be determined by using information thatidentifies a location of the vehicle on a map. Sensors for the positioncan include global positioning sensors (or GPS), maps and cameras.

An overview of the further processing of the signals is first givenbelow. During the detection of a collision, various cases are taken intoconsideration, which can also be filed as default values, models orreference values or reference thresholds in the detection units 11 or12. These cases include, for example, a collision between two vehiclesas a rear-end collision, a lateral collision or as a collision at anangle.

During the determination of predetermined movement following thecollision, various cases are considered, which can also be filed asdefault values, models or reference values or reference thresholds insystem/unit 11 or system/unit 12. These cases include, for example,undesirable movements such as longitudinal or lateral movements,undesirable yawing and rolling. If, following the collision the speed ofthe vehicle is considerably reduced, for example below a definedthreshold of e.g. 8 km/h, the movement following the collision can beclassified as not an undesirable movement.

After a collision and an undesirable movement following the collisionhave been detected, a collision flag and a flag for the undesirablemovement following the collision are set.

Next, the brake system is preloaded. Because this engagement is notnoticed by the driver, it can be immediately induced if there is asuspicion of the existence of a collision. A dedicated flag that can bereset by a PIB (Post Impact Braking) activation flag that can requestpre-charging of the brake from an external module. A confirmation canthen take place that the collision and the undesirable movement areconfirmed.

The autonomous brake system 1 can take over the function of a brakeassistance system (or Emergency Brakes Assist, EBA). The EBA function isactivated by the PIB activation flag and not, as with CMS/CADS systemsprior to an impact, by an optically based sensor. Here, after detectionof a collision and an undesirable movement following the collision, anemergency braking process is initiated if the driver initiates a brakingprocess. The emergency braking process produces full braking pressureeven if the driver produces less pedal pressure. The additional pressureis produced by a brake booster.

Now turning to FIG. 6 which shows steps of a method for an autonomousbrake function following a collision. During normal driving operation(at step 23) the controller 2 continuously samples the sensor signalsand evaluates them. At step 24 the controller decides whether acollision exists or not. This takes place according to the followingcriteria, whereby the following abbreviations and terminology are used:

-   -   longitudinal acceleration: a_(x)    -   lateral acceleration: a_(y)    -   yaw rate: ω_(z)    -   roll rate: ω_(x)    -   wheel speeds: ω_(i)    -   vehicle reference speed: v_(x)    -   flag indicating the impact phase: InImpact    -   flag in an uncontrollable impact: InUncontrollableImpact    -   flag indicating the post impact phase: PostImpact    -   deactivation override flag: DeactivationOverride

Interruption of the fuel supply is detected. A fuel supply will beinterrupted, for example if the longitudinal speed and/or lateral speedexceed or fall below a defined threshold.

FIG. 7 shows the limits or “range” for the longitudinal speed and thelateral speed. A modified fuel supply can be used with a reducedthreshold value as a trigger for the braking algorithm.

Airbag trigger signals can further trigger the detection of a collision.Modified signals that increase or reduce the sensitivity of the brakingassistance algorithm, can also be used here. Electronic stabilitycontrol (or ESC) sensor values can be used as further triggers for thedetection of a collision.

Even assuming a sensor fault, a collision can be detected with the ESCmotion sensors. The following variables are used: the last three valuesof the longitudinal acceleration; the last three values of the yaw rate;or relayed values of the real wheel speeds. In an initialization, thesensor signals, calculated variables and flags that are set in the rangeof the input variables are received and a global counter is started.System counters and timers are set accordingly.

The gradients of the longitudinal accelerations are calculated with thelast four sampled values for preparation of the longitudinalacceleration.da _(y) =a _(y) −a _(y) [z ₁]da _(y) [z ₁ ]=a _(y) [z ₁ ]−a _(y) [z ₂]da _(y) [z ₂ ]=a _(y) [z ₂ ]−a _(y) [z ₃]and the average gradient of the longitudinal acceleration during thelast four sampled values are calculated as follows:d ₄ a _(y) =a _(y) −a _(y) [z ₃]

It should be noted that the delta value is calculated over a sample timeof 10 ms, d₄a_(y) is averaged over four sample values, i.e. over 40 ms.

For preparation of the yaw rate, the gradients of the yaw rates arecalculated with the last four sampled values.dω _(z)=ω_(z)−ω_(z) [z ₁]dω _(z) [z ₁]=ω_(z) [z ₁]−ω_(z) [z ₂]dω _(z) [z ₂]=ω_(z) [z ₂]−ω_(z) [z ₃]and the mean gradient of the yaw rate during the last four sampledvalues:d ₄ω_(z)=ω_(z)−ω_(z) [z ₃]

It is to be noted that the delta value is calculated over a samplingtime of 10 ms, d₄ω_(z) is averaged over four sampled values, i.e. over40 ms. For preparation of the anticipated yaw rate, the yaw rate basedon the wheel speeds is calculated using the sensor signals for thespeeds of the two rear wheels.ω_(zwssr)=(w ₂ +w ₂ [z ₁ ]−w ₃ −w ₃ [z ₁])/2/t _(r)t_(r) is the rear axle displacement.

The gradients of the longitudinal accelerations are calculated with thelast four sampled values for preparation of the longitudinalacceleration.

A brake control time sequence is shown in FIG. 8. Following a collision21, a potential collision is detected, which entails the activation of athreat flag or hazard flag (Threat ON). Somewhat later, an aggressive orundesirable reaction or movement of the vehicle is detected and acorresponding flag is activated. In parallel with this, the collision isconfirmed. If the effects diminish or the driver takes over control, theflags and the actions are stopped or reset.

If the wheel speeds are outside a normal range for ABS operation, brakecontrol based on a slip ratio is replaced by brake control not based ona slip ratio, i.e. the system is not changed to the ABS mode. Instead, afixed amount of braking pressure P_(pibamax) is sent to all wheels,which is close to the maximum efficiency of the braking pressure. Ifthere is no collision according to the conditions and conflictresolutions, branching back to step 23 occurs. In the case of acollision, branching to step 25 occurs. In step 24 an undesirablemovement following a collision is also detected.

The brake system is pre-charged in step 25. For this purpose, followingdetection of the impact as determined by the flag PostImpact, a smalleramount of braking pressure P_(precharge) is produced to be sent to thebrake calipers in order to prevent potential hydraulic delays. Likewise,the sensitivity of the brake system can be increased in order to assistin faster braking initiation.

In step 26 it is detected whether the driver has an intention to brake.For this purpose, following the registration of the impact it isdetermined whether the driver is reacting to the event by releasing thegas pedal and possibly preparing for a braking process. To this end thecontroller 2 receives signals related to the positions and/or movementsof the pedals from the gas pedal encoder 5 and/or the brake pedalencoder 4.

If it is indicated that the driver has no intention to brake, thealgorithm branches to a step 27, according to which autonomous brakingtakes place. In the event of a detected intention to brake, branching tostep 28 takes place in order to support the braking process with thebrake system based on the detection of the driver's intention to brakeand the collision.

In step 29, conflicts between brake functions are resolved. Thus controlsignals, which are output for example by a brake assistance system basedon image processing sensors, are overridden by the brake systemdescribed, which is based on the determination of the collision. This isadvantageous, because the brake system described here is more reliablein the state following an impact.

Similar requests to the brake system 1 can be generated by other(software) modules, such as for example PIBA, ESC/RSC, TCS/ABS, CMbB(Collision Mitigation by Braking) or ACC (Adaptive Cruise Control).

Thus a decision strategy is provided to send a one-time or uniquerequest for triggering the brakes. A solution is proposed here using themaximum function.

In step 30 it is decided whether the support of the brake system isterminated after fulfillment of a termination criterion. If this is thecase, branching back to step 23, the normal mode, takes place. If thereis no termination criterion, branching to step 25 takes place. Also step27, according to which an autonomous braking process is active, branchesto step 30. The termination criterion can, for example, be stabilizationof the motor vehicle, whereby the normal safety systems are operationalagain, or a defined time period, for example 2.5 seconds, or the motorvehicle being stationary or if the driver operates the gas pedal for thefirst time post-collision or releases the brakes.

If the driver stops braking, but some other measurement values, such asa large yaw rate or a high speed of a wheel, are outside of normalvalues, the brake system continues to assist the braking process, untilthese values are within the normal range.

If the driver activates the brakes, but some other measurement values,such as a large yaw rate or a high speed of one or more wheels, areoutside of normal values, the brake system does not allow the brakingprocess.

If the driver deactivates the brakes too early, the brake systemcontinues to brake until for example a time period of 2.5 seconds haselapsed after setting the flag for the collision.

This function calculates three binary outputs; brake override, steeringoverride and gas pedal override. The brake override flag is set if thedriver has braked and has just released the brake pedal. In this casethe flag remains set for a defined period, for example of about onesecond.

Those familiar with the art to which this invention relates willrecognize various alternative designs and embodiments for practicing theinvention within the scope of the appended claims.

We claim:
 1. A method of controlling a vehicle, comprising: providing avehicle having a brake system configured to operate according to anominal mode, a first active braking mode, and a second active brakingmode, wherein in the nominal mode an applied braking pressure is basedon a driver braking request, in the first active braking mode theapplied braking pressure is based on a maximum braking pressure anddecreased in response to a driver release of a brake pedal, and in thesecond active braking mode the applied braking pressure is based on themaximum braking pressure; in response to a detected collision,controlling the brake system according to the first active braking mode;in response to the first active braking mode being active and no driverbraking request being anticipated, controlling the brake systemaccording to the second active braking mode; and in response to thefirst active braking mode or second active braking mode being active anda termination criterion being satisfied, controlling the brake systemaccording to the nominal mode.
 2. The method of claim 1, wherein thetermination criterion includes the vehicle being stabilized, acalibratable time interval expiring, or a driver actuation of a gaspedal.
 3. The method of claim 2, wherein the vehicle being stabilized isdetermined based on a motion sensor reading falling below a predefinedthreshold.
 4. The method of claim 1, further comprising, in response tothe first active braking mode being active, a driver braking requestbeing received, and the driver braking request being discontinued when amotion sensor reading exceeds a threshold, controlling the brake systemaccording to the second active braking mode.
 5. The method of claim 1,wherein the collision is detected based on an airbag activation, a fuelsupply shutting down, or a motion sensor reading exceeding a predefinedthreshold.
 6. A vehicle, comprising: a brake system; and a controllerconfigured to in response to a detected collision, control the brakesystem according to a first braking mode in which applied brakingpressure is based on a maximum braking pressure and decreased inresponse to a driver release of a brake pedal, to in response to thefirst braking mode being active and no driver braking request beinganticipated, control the brake system according to a second braking modein which applied braking pressure is based on the maximum brakingpressure, and to in response to the first active braking mode or secondactive braking mode being active and a termination criterion beingsatisfied, control the brake system according to a nominal mode in whichapplied braking pressure is based on a driver braking request.
 7. Thevehicle of claim 6, wherein the termination criterion includes thevehicle being stabilized, a calibratable time interval expiring, or adriver actuation of a gas pedal.
 8. The vehicle of claim 7, wherein thevehicle being stabilized is determined based on a motion sensor readingfalling below a predefined threshold.
 9. The vehicle of claim 6, whereinthe controller is further configured to, in response to the first activebraking mode being active, a driver braking request being received, andthe driver braking request being discontinued when a motion sensorreading exceeds a threshold, control the brake system according to thesecond active braking mode.
 10. The vehicle of claim 6, wherein thecollision is detected based on an airbag activation, a fuel supplyshutting down, or a motion sensor reading exceeding a predefinedthreshold.
 11. A method of controlling a vehicle comprising:automatically controlling brakes with a controller to provide brakingtorque based on a maximum braking pressure in response to a collisiondetected based on a yaw rate compared to an average gradient of yaw rateamong a plurality of yaw rate samples, and further based on alongitudinal acceleration parameter compared to an average gradient oflongitudinal acceleration among a plurality of acceleration measurementsamples.
 12. The method of claim 11, further comprising, in response toa driver braking request being received and a motion sensor readingfalling below a threshold, automatically controlling the vehicle brakesto decrease braking pressure in response to a driver release of a brakepedal.
 13. The method of claim 12, further comprising, in response tothe driver braking request received, a driver release of the brakepedal, and the motion sensor reading being above the threshold,automatically controlling the vehicle brakes to maintain the brakingtorque based on the maximum ABS braking pressure.
 14. The method ofclaim 11, further comprising, in response to a termination criterionbeing received, discontinuing the automatic controlling of the vehiclebrakes.
 15. The method of claim 14, wherein the termination criterionincludes a motion sensor reading falling below a threshold, acalibratable time interval expiring, or a driver actuation of a gaspedal.